Another set of acronym's you will see as reference to the old analog tones
CTCSS: Continuous Tone Coded Squelch System.
PL: Private Line (Motorola)
Channel Guard (General Electric)
Quiet Channel (RCA)
All four terms mean exactly the same thing and are interoperable.
There is also a group of "digital" tone sequences, One Example is DPL Which is Motorola's old name for Digital Private Line. These are NOT interoperable with the analog tone systems. But the voice is still analog and only the tone encoding is digital in this case.
None of these are to be confused with the digital voice formats; DMR, System Fusion, P25, D-Star etc.
If we haven't confused you yet, it is NOT for lack of trying.
